Berlin: As Europe's E. coli crisis wanes, some experts are now warning of a looming threat: possible long-term kidney complications for many of the victims.

Many of the roughly 3,200 E. coli patients are recovering and returning home, and only a handful of new cases are being reported.

But along with a record death toll of 38, the outbreak also produced an unprecedented number of patients with a rare ailment known as hemolytic uremic syndrome, or HUS, which can lead to kidney failure.

Germany usually sees some 40 to 50 such cases a year; 784 people suffered from HUS in the outbreak. The complication usually hits about 10 percent of E. coli patients and kills up to 5 percent of those infected.

Some experts warn that Germany could now face dozens of patients needing kidney transplants.

"We cannot forget these people," said Dr. Karl Lauterbach, a health expert with the opposition Social Democrats who is predicting that 50 to 100 could need long-term dialysis or an organ transplant -- a procedure for which they could wait up to a decade.

"We need more kidney donations, we need a better treatment system and in the future we cannot underestimate such infections."

The E. coli strain that broke out in Germany affected adults who were otherwise healthy and mostly aged between 20 and 50. German health authorities believe they may have been the hardest hit because they are typical consumers of vegetable sprouts, which have been identified as the source of the outbreak.

In previous E. coli outbreaks, up to half of patients who developed the kidney complication were still suffering from long-term side effects 10 to 20 years after first falling sick, including high blood pressure caused by dialysis.

In addition to possible kidney problems, people who have survived serious E. coli infections may also suffer from neurological damage, as the bacteria may have eaten away at blood vessels in the brain. That could mean suffering from seizures or epilepsy years after patients recover from their initial illness.

Dr. Friedrich Hagenmueller, the medical director of Asklepios Hospital Altona, in Hamburg, the center of the outbreak over the past weeks, said most patients have been recovering well, and cautioned it is too early to speculate about future complications.

"There is still a chance that many of these people will get well. We see a lot of young patients who are recovering very well," he said in a telephone interview.

"At the moment, nobody knows what percent of patients will suffer long-term effects."

According to Germany's Organ Transplant Foundation, some 8,000 patients were waiting for a kidney, while only about 2,900 transplants were conducted in 2010.

Lauterbach said that while the nation's health system could cope with the strain, being on long-term dialysis while awaiting a transplant would mean a severe drop in quality of life.

And even if a patient appears to have initially recovered from kidney failure, there could still be serious setbacks as time passes, said Dr. Charles Tomson, president of Britain's Renal Association.

"There may be a time bomb effect of people who recover enough kidney function, start passing urine, their kidneys start working well enough to clear waste products, but then those people may be at increased risk of kidney failure later because they've had a period of major kidney damage and it just takes less to upset them later," Tomson said.

Since the new E. coli strain appeared more lethal than related strains in the past, it was possible there would be more patients with complicated side effects in the future, he said.

In Germany, if a person has not signed up to be a donor, the next of kin must decide whether to donate in the event of sudden death.

That means a German can wait from seven to 10 years for a kidney, while patients seeking transplants in Britain or the United States face average wait times of around three to five years.

Studies commissioned by the German Foundation for Organ Transplant show that more than 80 percent of the population would be willing to donate organs, but only a fraction fill out the necessary paperwork. That leaves bereaved relatives forced to make the choice in a moment of duress. Most decide against it.

"There is not enough information about the issue," said Thomas Mehlitz, who is the transplant coordinator for Berlin's Charite Hospital and is faced with a constant lack of healthy organs needed for patients.